1. Field of the Invention
The present invention relates to a fractional caching method and an adaptive contents transmitting method using the same, and more particularly, to a fractional caching method, which is applied to a transcoding streaming server to transmit adaptive contents, and an adaptive contents transmitting method using the same.
2. Description of the Related Art
Applications of Internet, which is a computer communication network for connecting all nations in the world, are increasing as network performance and computing performance are improved. Accordingly, request for receiving a real-time service of media contents seamlessly at high speed is increasing.
As a digital expressing method of the media contents is diversified and sophisticated, an adaptive contents transmitting technology for transforming and providing media contents of a certain type into media contents of other type is increasingly required.
That is, the most important thing is to transmit the media contents seamlessly at high speed and provide media contents of a type which is proper to an environment of a user terminal such as a network bandwidth, a file format, and a compression technology.
A conventional adaptive contents transmitting method adopted an offline method of selecting and providing proper media content according to a user terminal type and a network bandwidth type in a state that diverse types of destination are formed and stored through a transcoder in advance with respect to one source type. However, since the types of the user terminals determining the destination type have been changed very fast, an on-the-fly method is also adopted to support diverse types of user terminals. In the on-the-fly method, the media contents are provided to the user terminal by performing transcoding in real time when the user requests streaming.
A server for performing transcoding and streaming in conformity with the types of the user terminal and the network bandwidth in real time upon request of the user is called a transcoding proxy streaming server. Since a proxy extension model having a transcoding function of the on-the-fly method requires a quantity of Central Processing Unit (CPU) loads due to characteristics of the transcoding, the proxy extension model is realized as a proxy cluster method for connecting a plurality of servers.
In the streaming server and the proxy cluster including the transcoding function, it is necessary to instantly change a destination type through caching of an original media content of a source type to provide a fast service. Therefore, a new caching policy for supporting diverse destination types by efficiently using a limited caching space and providing a seamless service at high speed is required.